The aim of the proposed This Mentored Research Scientist Development Award (MRSDA) is to train the candidate in affective neuroscience and adolescent development relevant to understanding the role of positive emotionality, a potential endophenotype, in the development of depression in youth. Understanding the role of endophenotypes is critical for identifying those at greatest risk for depression. Although a number of studies demonstrate that positive emotionality is implicated in depression and risk for depression, few have examined reward-related brain function in the service of conducting critical tests of endophenotypes for depression. Adolescence is a particularly important point in the lifespan to address this issue because it is the peak time of onset for depression. The candidate has expertise in assessing positive emotionality using behavioral and self- report methods, early childhood development in offspring of depressed parents, youth depression, and longitudinal data analysis. He seeks to build on this expertise through this MRSDA to (1) learn from expert mentors and consultants about functional magnetic resonance imaging (fMRI) approaches to investigating adolescent brain development, reward-related brain function, and pathophysiology of depression; (2) complete coursework in affective neuroscience, fMRI, data analysis, and research ethics; (3) attend workshops on fMRI and neuroimaging data analysis; and (4) conduct a study examining critical tests of positive emotionality, operationalized as reward-related brain functioning, as an endophenotype for depression. The University of Pittsburgh is a phenomenal environment to pursue this training as it has extensive resources in the areas of affective neuroscience, adolescent development, and adolescent depression. The candidate's mentors, Drs. Erika Forbes and Jennifer Silk, have extensive expertise in affect-related brain functioning in depression, adolescent development, and adolescent depression. The proposed training will occur in the context of a longitudinal study examining: (1) differences in reward-related brain functioning between non-depressed adolescents of parents with (N = 45) and without (N = 30) a history of depression; (2) the prospective relationship between reward-related brain functioning and depressive symptoms over an eighteen month period; and (3) prediction of the development of depressive symptoms prospectively predicted by reward- related brain functioning and self-report measures of positive emotionality. This will provide evidence for the comparative utility of each approach of identifying those at risk for depression. Consistent with the priorities outlined by the National Institute of Mental Health, the proposed MRSDA has the potential to address mechanisms of risk through investigating behavioral and biological processes. Further, the combination of training and research will serve as a spring board for the candidate's independent research career to further elucidate the role of positive emotionality in the development of depression during adolescence.